RESUMO
Fracture matches are considered the strongest conclusion in the forensic examination of rigid materials, such as glass, metal, and paint. However, publications that support the fracture matching of polymeric films, such as tape backings, are limited. This study was designed to determine the validity and error rate associated with conducting end-match (fracture match) examinations on vinyl electrical tape. Test designs varied the source roll of tape, test preparer, or mode of separation from the roll. Results indicated that each affected the resulting severed tape ends. The analysts examining the end matches also had an effect on the results. Eight end matches in the study were not identified by the initial analysts and were considered inconclusive. One end match was misidentified, resulting in one false positive and an error rate of 0.049%. These results support a comprehensive physical and chemical tape comparison regardless of indications of an end match.
RESUMO
Fracture matches are considered to be the strongest association achievable in forensic examinations of glass, metal, wood, plastic, paint, tape, and other trace evidence. Despite being fairly routine examinations, few publications exist to support their admissibility in court. This study was designed, using duct tape as the fractured medium, to determine the validity and error rate associated with conducting end match (fracture match) examinations on this material. Five test designs, which varied either the source roll of tape or manner of separation (torn or cut) from the roll, were administered to four analysts with instructions to examine the assigned test sets for end matches. If an end match was not identified by the initial analyst, the entire test set was independently evaluated by the remaining three analysts. Results indicated that while tape grade did not hinder end match identification, the manner of separation could affect results.
